title: Thyroid nodules (≥4 cm): can ultrasound and cytology reliably exclude cancer?
abstract: BACKGROUND
  Whether a threshold nodule size should prompt diagnostic thyroidectomy remains controversial. We examined a consecutive series of patients who all had thyroidectomy for a ≥4 cm nodule to determine (1) the incidence of thyroid cancer (TC) and (2) if malignant nodules could accurately be diagnosed preoperatively by ultrasound (US), fine needle aspiration biopsy (FNAB) cytology and molecular testing.
  
  
  METHODS
  As a prospective management strategy, 361 patients with 382 nodules ≥4 cm by preoperative US had thyroidectomy from 1/07 to 3/12.
  
  
  RESULTS
  The incidence of a clinically significant TC within the ≥4 cm nodule was 22 % (83/382 nodules). The presence of suspicious US features did not discriminate malignant from benign nodules. Moreover, in 86 nodules ≥4 cm with no suspicious US features, the risk of TC within the nodule was 20 %. US-guided FNAB was performed for 290 nodules, and the risk of malignancy increased stepwise from 10.4 % for cytologically benign nodules, 29.6 % for cytologically indeterminate nodules and 100 % for malignant FNAB results. Molecular testing was positive in 9.3 % (10/107) of tested FNAB specimens, and all ten were histologic TC.
  
  
  CONCLUSIONS
  In a large consecutive series in which all ≥4 cm nodules had histology and were systematically evaluated by preoperative US and US-guided FNAB, the incidence of TC within the nodule was 22 %. The false negative rate of benign cytology was 10.4 %, and the absence of suspicious US features did not reliably exclude malignancy. At minimum, thyroid lobectomy should be strongly considered for all nodules ≥4 cm.
authors.affiliation: Department of Surgery, University of Pittsburgh School of Medicine, Suite 101 - 3471 Fifth Avenue, Pittsburgh, PA, 15213, USA.
authors.forename: Laura I
authors.initials: LI
authors.lastname: Wharry
authors.forename: Kelly L
authors.initials: KL
authors.lastname: McCoy
authors.forename: Michael T
authors.initials: MT
authors.lastname: Stang
authors.forename: Michaele J
authors.initials: MJ
authors.lastname: Armstrong
authors.forename: Shane O
authors.initials: SO
authors.lastname: LeBeau
authors.forename: Mitch E
authors.initials: ME
authors.lastname: Tublin
authors.forename: Biatta
authors.initials: B
authors.lastname: Sholosh
authors.forename: Ari
authors.initials: A
authors.lastname: Silbermann
authors.forename: N Paul
authors.initials: NP
authors.lastname: Ohori
authors.forename: Yuri E
authors.initials: YE
authors.lastname: Nikiforov
authors.forename: Steven P
authors.initials: SP
authors.lastname: Hodak
authors.forename: Sally E
authors.initials: SE
authors.lastname: Carty
authors.forename: Linwah
authors.initials: L
authors.lastname: Yip
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044963:Biopsy, Fine-Needle; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D013965:Thyroidectomy; D014463:Ultrasonography